13- Contributions Of Cerebellum And Basal Nuclei To Motor Function II

Question 1

Is the putamen circuit a(n) indirect/direct basal nuclei circuit?

Answer 1

Direct

Question 2

Is the caudate nucleus circuit a(n) indirect/ direct basal nuclei pathway?

Answer 2

Indirect

Question 3

The basal nuclei receive most of their input from the cerebral cortex and return most of their output where?

Answer 3

To the cerebral cortex

Question 4

What is the principle roles of the basal nuclei?

Answer 4

To work with the corticospinal system to modulate thalamic output to the motor cortex to plan and execute smooth movements

Question 5

The basal nuclei consist of paired nuclei. What are they?

Answer 5

• striatum (–caudate nucleus– and the putamen)
• globus pallidus
• substantia nigra
• subthalamic nucleus

Question 6

Almost all motor and sensory nerve fibers connecting the spinal cord to the cortex pass through the space that lies between the what major masses of the basal nuclei?

Answer 6

The caudate nucleus and the putamen

Question 7

What is the space between the caudate nucleus and the putamen called?

Answer 7

The internal capsule

Question 8

The striatum consist of what nuclei?

Answer 8

• caudate nucleus

- putamen

Question 9

This circuit/pathway is for subconscious execution of learned pattern movements?

Answer 9

• Putamen circuit (direct pathway)

Question 10

Is the putamen pathway excitatory or inhibitory?

Answer 10

• overall excitatory – tends to increase motor activity

Question 11

Connections between the striatum and the substantia nigra use what neurotransmitter?

Answer 11

Dopamine

Question 12

Dopamine is ___________ on the indirect pathway?

Answer 12

Inhibitory (uses D2 receptors)

Question 13

Dopamine is __________ on the direct pathway?

Answer 13

Excitatory (uses D1 receptors)

Question 14

Because of the receptors used in the pathway, the overall effect of dopamine in the putamen circuit (direct pathway) Is what?

Answer 14

Excitatory (uses D1 receptors)

Question 15

The IGP/SubNigRet is normally ________ and sends __________ signals to the thalamus. Exciting the putamen _________ the IGP/SubNigRet and allows the thalamus to send __________ signals to the motor cortex?

Answer 15

Active, inhibitory. Inhibits, excitatory.

Question 16

Lesions in the globus pallidus can lead to?

Answer 16

Spontaneous and often continuous writhing movements of a hand, an arm, the neck, or the face—-(called Athetosis)

Question 17

Lesions in the subthalamic nuclei can lead to?

Answer 17

Sudden flailing movements of an entire limb—(called hemiballismus)

Question 18

Lesions in the striatum (caudate nucleus and putamen) can lead to?

Answer 18

Flicking movements in the hands, face, and other parts of the body—(called chorea)

Question 19

Lesions in the substantia nigra can lead to?

Answer 19

To the common and extremely severe disease of rigidity, akinesia, and tremors—(aka Parkinson’s disease)

Question 20

Is the caudate circuit (indirect pathway) inhibitory or excitatory?

Answer 20

Overall inhibitory– tends to decrease motor activity

Question 21

This circuit/pathway plays a major role in cognitive control of motor activity?

Answer 21

Caudate circuit (indirect pathway)

Question 22

This pathway/circuit is for cognitive planning of sequential and parallel motor patterns?

Answer 22

Caudate circuit (indirect pathway)

Question 23

Substantia nigra—-> causdate nucleus. What NT?

Answer 23

Dopamine (inhibitory)

Question 24

Caudate nucleus and putamen—->globus pallidus and substantia nigra. What NT?

Answer 24

GABA (inhibitory)

Question 25

Cortex---->caudate nucleus and putamen. What NT?

Answer 25

Acetylcholine (excitatory)

Question 26

What neurotransmitters are involved in multiple pathways from the brain stem?

Answer 26

- norepinephrine - serotonin (inhibitory) - encephalin

Question 27

These pathways provide most of the excitatory signals in the basal ganglia?

Answer 27

Multiple glutamate pathways

Question 28

What is another name for paralysis agitans?

Answer 28

Parkinson's disease

Question 29

What are the characteristics displayed by Parkinson's?

Answer 29

- rigidity of much of body musculature - involuntary tremors of involved areas even at rest at a fixed rate - serious difficulty in initiating movement (akinesia) - postural instability - dysphasia, speech disorders, gait disturbances, fatigue

Question 30

Parkinson's results from what?

Answer 30

Widespread destruction of pars compacta of substantia nigra that sends dopaminergic fibers the the caudate nucleus and putamen (striatum)

Question 31

With Parkinson's, dopaminergic pathways to direct and indirect pathways are lost. What does this result in?

Answer 31

- direct pathway (putamen circuit) loses some of its excitatory input - indirect pathway (caudate circuit) loses some of its inhibitory pathway ** either way there is decrease motor activity**

Question 32

People with Huntington's disease usually become symptomatic around what age?

Answer 32

30-40 years of age

Question 33

What are the characteristics displayed by Huntington's?

Answer 33

- flicking movements of individual muscle - progressive sever distortional movements of entire body - severe dementia - motor dysfunctions

Question 34

What is thought to be the reason for the abnormal movements in those with Huntington's?

Answer 34

- Loss of most of the cell bodies of GABA-secreting neurons of the caudate nucleus and putamen AND of Ach neurons in other parts of the brain - the axon terminals of the GABA neurons normally inhibit portions of the globus pallidus and substantia nigra. This loss of inhibition is believed to allow spontaneous outbursts of the globus pallidus and substantia nigra activity that cause the distortional movements

Question 35

What are the 2 major basal nuclei circuits?

Answer 35

- Putamen circuit (direct) | - Caudate nucleus circuit (indirect)